One example of a conventional electronic component mounting apparatus is shown in FIG. 6. Electronic component mounting apparatus 30 comprises a loader 39 for carrying in and out a circuit board 1, a component feeding unit 35 which stocks trays 3 loaded with electronic components 2, each tray 3 being fixedly placed on tray shelves stacked in a tray magazine in such a way that the tray 3 accommodating components 2 of desired type is vertically transferred to a proper tray feeding position, a plurality of component feeder reels 32 for supplying electronic components 31 which are stocked in a row on a tape-like member wound around a reel, a mounting head 33 equipped with a suction nozzle 34 which picks up electronic components 2(31) by suction from the component feeding unit 35 or the component feeder reels 32 and mounts them on to the circuit board 1 located at a prescribed mounting position, and an X-Y robot 37 for causing the mounting head 33 to move freely on a plane defined by X and Y axes.
In the above-described arrangement, the mounting head 33 is freely moved by the X-Y robot 37 to pick up components 2(31) from the component feeder reels 32 or the component feeding unit 35 with the suction nozzle 34 and mount them on to the circuit board 1 located at a prescribed position. The posture of the component 2(31) held by the suction nozzle 34 is checked by a component recognizing camera 38 and corrected so as to be mounted precisely at a given mounting position.
Such component mounting action by the mounting head 33 is repeated until all of a given number of components required for one circuit board are completely mounted. Generally, smaller components such as chip components are fed from the component feeder reels 32 whereas components of larger size such as IC or LSI are supplied from the component feeding unit 35 in the apparatus 30 of such kind.
Since the mounting head 33 has only a single suction nozzle 34 in the above described apparatus 30, the mounting head 33 needs to travel between the component feeder reels 32 or the component feeding unit 35 and the mounting position on the circuit board 1 via the recognizing camera each time one component 2(31) is mounted, thus having rather low productivity.
By providing the mounting head 33 with several nozzles so that components 2 are picked up in plurality at one time to perform continuous mounting action, the productivity may be enhanced. However, in order to pick up a plurality of components 2 supplied from the component feeding unit 35, the components 2 need to be preliminarily transferred to a prescribed position and aligned in a given mounting order. For that purpose, it is necessary to provide a transfer mechanism which is capable of picking up components 2 and moving along at least two directions (on X-Y plane) and a temporary holding means on which components are held, causing the entire structure-of the apparatus to be large and complicated.
An object of the present invention is to provide a method and apparatus for mounting electronic components having a component transfer mechanism of simple structure for performing efficient component mounting action with a mounting head provided with several nozzles for picking up a plurality of components at one time, whereby supplying and transferring electronic components are efficiently effected thus improving productivity.